Hydroponics is an alternative system of growing plants without soil. Instead of soil, an inert media is used into which a nutrient solution containing essential elements is added for a plant's normal growth and development.
Existing commercial hydroponics systems vary in terms of form, size, and type of materials. They need electric driven pumps for aeration and irrigation. During a power failure, these systems encounter water logging and consequently lead to the death of plants. Thus, a Simple Nutrient Addition Program (SNAP) (Fig. 1) was developed. This system does not require electricity or aeration, is low cost, and uses simple methods.
The SNAP hydroponics system is appropriate in urban areas where soil or space for growing crops is not adequate. It may be done in apartments or townhouses where small terraces can be used in growing crops for home consumption. The small space is easy to protect against rain and strong sunlight. The system requires covered containers or pots that can hold about 2 liters of water, SNAP fertilizer, and seeds of chosen heat-tolerant vegetables.
Vegetables like lettuce, sweet pepper, cucumber, and celery were successfully grown using the SNAP hydroponics system. The use of this system can improve household income and increase the per capita vegetable consumption.
In the trials conducted during the cold months on lettuce, the vegetables performed better in SNAP culture than in the field. Economic analysis of adopting SNAP hydroponics for commercial lettuce production in a 200 m2 area showed that it requires an initial investment of P66,925 and an annual production cost of P65,555.83 ($1=P56). Assuming ten croppings per year at the average lettuce price of P50/kilo, the return on investment will be 51%. The investment cost can be recovered in less than 2 years.
Prepare materials like seedling plugs ( Fig. 2) and culture pot. For seedling plugs, use 6 oz styrofoam cups with the center bottom (2.5-cm diameter) cut off. Place a garden net in the cutoff portion of the cup. Place 1.5 cm thick coir dust and 1.5 cm sand at the bottom of the cup.
For culture pots, use recycled styrofoam grape boxes ( Fig. 3). Make holes big enough to hold the seedling plugs by their necks. Line the bottom with polyethylene plastic sheet (0.02 mm thick) to prevent the solution from leaking. Place the culture pots inside the greenhouse.
Prepare the seedlings. Sow seeds in seed boxes. Transplant seedlings in seedling plugs 2 weeks after seedling emergence. Place in shallow trays with 1 cm nutrient solution. If root length grows from 1-2 cm, transfer to culture pots. The bottom of the seedling plugs should be submerged by about 1 cm in the culture pot.
After two weeks, replenish the water with nutrient solution. Allow the nutrient solution to go below the bottom of the cups from 1-3 cm to enhance passive aeration.
Figure 1 A Snap Hydroponics Setup
Figure 2 Seedling Plug
Figure 3 Grape Fruit Styrofoam Box Used to Hold Seedling Plug and Nutrient Solution
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